Effects of cytochalasin B, colchicine and vincristine on the metabolism of isolated fat-cells |
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Authors: | Ernest G. Loten and Bernard Jeanrenaud |
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Affiliation: | Laboratoires de Recherches Médicales, 64 Avenue de la Roseraie, 1211 Geneva 4, Switzerland |
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Abstract: | 1. Colchicine and vincristine only slightly inhibit the metabolism of glucose to CO(2) and lipids by isolated fat-cells. 2. Prolonged incubation with these agents causes no further inhibition. 3. Cytochalasin B, however, inhibits glucose metabolism to both CO(2) and lipids in fat-cells. 4. However, at a concentration that causes a strong inhibition of glucose metabolism cytochalasin B is without effect on the metabolism of pyruvate, lactate or arginine to these end products. The uptake of labelled alpha-aminoisobutyrate is likewise not modified. Similarly it does not affect release of glycerol or free fatty acid, or the actions of adrenaline, insulin or caffeine on these parameters. At 10mug/ml it slightly lowers ATP concentrations, an effect that does not occur at 2mug/ml. 5. The transport of fructose into adipocytes by a specific fructose-transport system is also not affected by the agent, but the uptake of 2-deoxyglucose is strongly inhibited. It is concluded that cytochalasin B may specifically inhibit the glucose-transport system of isolated fat-cells. 6. Cytochalasin A has a much weaker action than cytochalasin B on glucose metabolism. |
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